Right, things/animals/people have value beyond their economic value. And to make decisions, we need to quantify in some way what this value is. To see this, consider a risk/cost curve for an environmental cleanup:

$100k : 1000 micromorts

$300k : 100 micromorts

$500k : 10 micromorts

$1m : 8 micromorts

$2m : 6 micromorts

$10m : 4 micromorts

$1b : 2 micromorts

$100b : 0.5 micromorts

Practically speaking, there is a need to make decisions which involve tradeoffs between money and other forms of value. Making these kinds of decisions rationally means quantifying non-economic forms of value.

Also, as more food for thought, consider the death penalty, in which a society deems that the true "value" of a person -- distinct from their economic value -- is negative.